The present invention relates generally to data processing and display systems, and more particularly to a bus mountable VGA controller card for use on IBM personal computer products namely, the IBM PC, PC/XT, PC/AT, and PS/2 and their one-hundred percent compatable clone computer products (hereinafter collectively referred to as IBM PC computers) to provide VGA (video graphic array) standard signals to drive conventional cathode ray tube (CRT) and flat panel displays. (IBM, PC/XT, and PC/AT are registered trademarks of International Business Machines).
Since initial introduction in the late-1960's, the personal computer has become the mainstay of both small and large businesses alike. With specific reference to IBM PC Computers, there has been a recent demand for enhanced video graphic capability to allow such personal computers to meet the more sophisticated demands of the marketplace. Pursuant to this demand, EGA (enhanced graphic array) graphics became the initial industry standard for business applications of personal computers which EGA standard offered a 640 by 350 pixel by 16 color resolution. By use of such EGA standards on the IBM PC computers and ther industry standard clones, such IBM personal computers were capable of providing video graphics to personal computer users.
In recognizing the substantial demand for improved video graphic capability on personal computers, International Business Machines (IBM) in 1987 introduced its PS/2 (trademark of International Business Machines) personal computer which adopted a new graphic standard, i.e. the VGA standard. Unlike the EGA standard, the VGA standard is able to both read and write hardware registers and offers increased 640.times.480 color resolution. The new IBM VGA standard as adopted on the IBM PS/2 computer, has been recognized as providing a substantial improvement in the art, and use of the standard is contemplated far into the future.
In view of the enhanced graphic capabilities of the VGA standard, owners of the previous PC, PC/XT and PC/AT personal computers have been faced with the decision of either purchasing a new PS/2 system which possesses the new VGA standard, or alternatively attempting to upgrade their existing PC, PC/XT, or PC/AT system to emulate the VGA standard. As will be recognized, the purchasing of the new PS/2 system proves to be a costly capital expenditure and hence is prohibitive. In relation to such upgrading to the VGA standard, VGA boards have recently been introduced into the marketplace which may be installed upon the IBM PC, PC/XT or PC/AT computers to emulate the new VGA standard. Examples of such VGA boards comprise those manufactured by Everex, Intelligent Data Systems, Paradise Systems, Sigma Designs, Tatung, Taxan, Tecmar, and Video Seven. Such VGA boards have generally failed to be completely interchangeable in functionality with the VGA standard because they typically embodied only (basic input output system) compatability and not hardware register compatability (hardware compatability) with the VGA standard. As such, the prior art VGA boards, although touting to be the functional equivalent of the VGA standard of the PS/2 system have generally failed to be completely 100% compatable with the same. As such there exists a substantial need in the art for an improved VGA controller card or board which is 100% compatable with IBM PC computers to provide VGA standard signals to drive conventional CRT displays.
In addition, in recent years, flat panel displays have been introduced into the marketplace which serve as a dominant future substitute for conventional CRT display systems. The advantage of such flat panel displays over conventional CRT displays is their reduced power consumption, reduced physical size and reduced costs as well as improved environmental aspects such as reduced radiation exposure and/or leakage. Although the prior art VGA boards discussed above have been developed for use with conventional CRT displays, they have been completely unavailable for use on flat panel displays due the different timing frequencies and operational characteristics associated with the flat panel displays. As such, to date there is a substantial void in the prior art to allow VGA standard graphics for use with flat panel displays. Thus, there additionally exists a substantial need in the art for a VGA controller to enable use of the VGA standard on conventional flat panel displays.
Additionally, the VGA standard implemented through the PS/2 system is additionally incapable of being utilized to drive flat panel displays. Thus there exists a need in the art for a VGA controller which will enable implementation of the VGA standard on both flat panel displays and well as CRT display systems.